Surgical instruments of this type are used, for example when ligating a blood vessel, organ or the like. In the case of such surgical--usually endoscopic--operations, a thread or a loop is initially introduced into the body or into the body cavity via a first puncture channel. This thread is then placed at the required point within the body cavity by means of a surgical instrument or thread manipulator of the afore-mentioned type. The thread manipulator is usually introduced into the body cavity via a further puncture channel, for example via the instrument channel of an endoscope or another insertion sleeve.
In accordance with the state of the art, gripping forceps are usually used as a thread manipulator. They have two handles at the proximal end which are connected to the mouth part arranged at the distal end by means of a shaft with an actuation device arranged therein. The handling of a thread or a loop within the body cavity using gripping forceps of this type is problematic in certain circumstances. Since the thread material is inherently relatively stiff per se, it is wet with liquid when it is introduced into the body cavity and then becomes very unstable as a result of absorbing moisture. In addition, it becomes sensitive to plastic deformations and damage, as a result of which the guaranteed strength values of the thread material may be impaired so as to be unusable. Since the mouth force in gripping forceps of this type is not usually limited, in practice damage to the thread may easily occur. Moreover, handling of the gripping forceps requires some skill, since two handles have to be operated. This requires awkward gripping of the handles of the gripping forceps, particularly when turning the thread.